WO2021056425A1 - 滤光片、指纹检测的装置和电子设备 - Google Patents

滤光片、指纹检测的装置和电子设备 Download PDF

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Publication number
WO2021056425A1
WO2021056425A1 PCT/CN2019/108584 CN2019108584W WO2021056425A1 WO 2021056425 A1 WO2021056425 A1 WO 2021056425A1 CN 2019108584 W CN2019108584 W CN 2019108584W WO 2021056425 A1 WO2021056425 A1 WO 2021056425A1
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WIPO (PCT)
Prior art keywords
optical
layer
film layer
light
substrate
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PCT/CN2019/108584
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English (en)
French (fr)
Inventor
高攀
吴宝全
刘辰锦
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深圳市汇顶科技股份有限公司
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Application filed by 深圳市汇顶科技股份有限公司 filed Critical 深圳市汇顶科技股份有限公司
Priority to CN201980004112.5A priority Critical patent/CN111066032B/zh
Priority to PCT/CN2019/108584 priority patent/WO2021056425A1/zh
Publication of WO2021056425A1 publication Critical patent/WO2021056425A1/zh

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    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
    • G06V40/00—Recognition of biometric, human-related or animal-related patterns in image or video data
    • G06V40/10—Human or animal bodies, e.g. vehicle occupants or pedestrians; Body parts, e.g. hands
    • G06V40/12—Fingerprints or palmprints
    • G06V40/13—Sensors therefor
    • G06V40/1324—Sensors therefor by using geometrical optics, e.g. using prisms
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
    • G06V10/00—Arrangements for image or video recognition or understanding
    • G06V10/10—Image acquisition
    • G06V10/12—Details of acquisition arrangements; Constructional details thereof
    • G06V10/14—Optical characteristics of the device performing the acquisition or on the illumination arrangements
    • G06V10/143—Sensing or illuminating at different wavelengths
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
    • G06V10/00—Arrangements for image or video recognition or understanding
    • G06V10/10—Image acquisition
    • G06V10/12—Details of acquisition arrangements; Constructional details thereof
    • G06V10/14—Optical characteristics of the device performing the acquisition or on the illumination arrangements
    • G06V10/147—Details of sensors, e.g. sensor lenses

Definitions

  • the embodiments of the present application relate to the field of biometric identification, and more specifically, to a filter, a fingerprint detection device, and an electronic device.
  • the optical fingerprint module collects the light reflected or transmitted on the finger and then returns, and realizes fingerprint recognition under the optical screen according to the fingerprint information of the finger carried in the light.
  • light in non-target wavelength bands such as red light wave band and infrared wave band light
  • the red light and infrared light in the sunlight can directly pass through the finger to reach the optical fingerprint module, so that the light carrying the fingerprint signal is submerged in the background noise of red light and infrared light, affecting The performance of fingerprint detection under the optical screen.
  • the embodiments of the present application provide a filter, a fingerprint detection device, and an electronic device, which will not affect the user's visual experience while ensuring the fingerprint detection performance, and has good structural stability.
  • a filter is provided, the filter is disposed between the display screen and the optical fingerprint sensor, and the optical fingerprint sensor is used to detect the light signal returned by the finger above the display screen.
  • the optical filter is used to filter the optical signal in the non-target wavelength band in the optical path of the optical signal transmitted to the optical fingerprint sensor.
  • the optical signal in the non-target wavelength band includes the optical signal in the red wavelength band and the optical signal in the infrared wavelength band
  • the filter includes: a substrate; at least one cut-off film layer for reflecting the optical signal of the non-target wavelength band, wherein the at least one cut-off film layer is located on both sides of the substrate; and, at least one absorber The layer is used to absorb the optical signal in the non-target waveband.
  • the at least one absorption layer includes an ink layer and/or a cyan paint layer.
  • the at least one cut-off film layer includes an IR film layer and/or a UV film layer.
  • the cut-off wavelength of the red light IR film layer is between 620 nanometers and 680 nanometers.
  • the cut-off wavelength of the violet UV film layer is between 400 nanometers and 420 nanometers.
  • the at least one absorption layer includes an ink layer, wherein the ink layer is coated on the upper surface and/or the lower surface of the substrate.
  • the upper surface of the substrate is covered with the UV film layer, and the lower surface of the substrate is sequentially covered with the ink layer and the IR film layer.
  • the upper surface of the substrate is sequentially covered with the ink layer and the UV film layer, and the lower surface of the substrate is covered with the IR film layer.
  • the upper surface of the substrate is sequentially covered with the ink layer and the UV film layer, and the lower surface of the substrate is sequentially covered with the ink layer and the IR film layer.
  • the at least one absorption layer includes a cyan paint layer, wherein the cyan paint layer is located on the outermost side of the filter.
  • the upper surface of the substrate is sequentially covered with the UV film layer and the cyan paint layer, and the lower surface of the substrate is covered with the IR film layer.
  • the upper surface of the substrate is covered with the UV film layer, and the lower surface covering the substrate is sequentially covered with the IR film layer and the cyan paint layer.
  • the upper surface of the substrate is sequentially covered with the UV film layer and the cyan paint layer
  • the lower surface of the substrate is sequentially covered with the IR film layer and the cyan paint layer .
  • the wavelength of the optical signal in the red wavelength band in the non-target wavelength band is between 620 nanometers and 770 nanometers
  • the wavelength of the optical signal in the infrared wavelength band in the non-target wavelength band is between 770 nanometers and 1000 nanometers. Between nanometers.
  • the number of coating layers of the at least one cut-off film layer is between 10-80.
  • the thickness of the at least one absorption layer is between 1-30 microns.
  • the multiple filters further include: an AR film layer, which is used to improve the transmittance of the filters to light of the target wavelength band.
  • the substrate is glass or resin.
  • the light transmittance of the substrate to optical signals with a wavelength of 450 nm to 600 nm is 80%-90%.
  • the at least one cut-off film layer is formed by sputtering, coating or deposition.
  • the filter is disposed between the display screen and the light guide layer, and the light guide layer is used to converge the optical signal of the target wavelength band after passing through the filter to The optical fingerprint sensor.
  • the light guide layer includes an optical collimator, a lens, or a microlens array.
  • a fingerprint detection device in a second aspect, includes:
  • the first aspect or the filter in any possible implementation of the first aspect is
  • an electronic device including:
  • the fingerprint detection device in the second aspect or any possible implementation of the second aspect.
  • FIGS 1A and 2A are schematic diagrams of electronic devices to which the present application can be applied.
  • Figures 1B and 2B are schematic cross-sectional views of the electronic device shown in Figures 1A and 2A along the A-A' direction, respectively.
  • Figure 3 is a schematic diagram of a possible optical filter structure.
  • Fig. 4 is a schematic diagram of a possible optical filter structure.
  • Fig. 5 is a schematic block diagram of an optical filter according to an embodiment of the present application.
  • Fig. 6 is a possible implementation based on the filter shown in Fig. 5.
  • FIG. 7 is a possible implementation based on the filter shown in FIG. 5.
  • FIG. 8 is a possible implementation based on the filter shown in FIG. 5.
  • FIG. 9 is a possible implementation based on the filter shown in FIG. 5.
  • FIG. 10 is a possible implementation based on the filter shown in FIG. 5.
  • FIG. 11 is a possible implementation based on the filter shown in FIG. 5.
  • FIG. 12 is a schematic structural diagram of a fingerprint detection device according to an embodiment of the present application.
  • FIG. 13 is a schematic block diagram of a fingerprint detection device according to an embodiment of the present application.
  • the embodiments of this application can be applied to fingerprint systems, including but not limited to optical, ultrasonic or other fingerprint identification systems and medical diagnostic products based on optical, ultrasonic or other fingerprint imaging.
  • the embodiments of this application only take optical fingerprint systems as an example
  • the embodiments of the present application should not constitute any limitation, and the embodiments of the present application are also applicable to other systems that use optical, ultrasonic, or other imaging technologies.
  • the optical fingerprint system provided in the embodiments of the present application can be applied to smart phones, tablet computers, and other mobile terminals with display screens or other electronic devices; more specifically, in the above electronic devices, the optical fingerprint The module can be set in a partial area or the entire area under the display screen to form an under-display or under-screen optical fingerprint system.
  • the optical fingerprint module may also be partially or fully integrated into the display screen of the electronic device, thereby forming an in-display or in-screen optical fingerprint system.
  • the fingerprint recognition technology under the optical screen uses the light returned from the top surface of the device display component to perform fingerprint sensing and other sensing operations.
  • the returned light carries information about objects that are in contact with the top surface, such as a finger.
  • the optical fingerprint detection of the specific optical sensor module located under the display screen is realized.
  • the design of the optical sensor module can be to achieve desired optical imaging by appropriately configuring optical elements for collecting and detecting the returned light.
  • Figures 1A and 2A show schematic diagrams of electronic devices to which the embodiments of the present application can be applied.
  • 1A and 2A are schematic diagrams of the orientation of the electronic device 10
  • Figs. 1B and 2B are schematic partial cross-sectional diagrams of the electronic device 10 shown in Figs. 1A and 2A along the direction A-A', respectively.
  • the electronic device 10 includes a display screen 120 and an optical fingerprint module 130.
  • the optical fingerprint module 130 is arranged in a partial area below the display screen 120.
  • the optical fingerprint module 130 includes an optical fingerprint sensor, and the optical fingerprint sensor includes a sensing array 133 having a plurality of optical sensing units 131 (also referred to as pixels, photosensitive pixels, pixel units, etc.).
  • the area where the sensing array 133 is located or its sensing area is the fingerprint detection area 103 of the optical fingerprint module 130. As shown in FIG. 1A, the fingerprint detection area 103 is located in the display area of the display screen 120.
  • the optical fingerprint module 130 may also be arranged in other positions, such as arranged on the side of the display screen 120 or the non-transmissive area at the edge of the electronic device 10, and is designed by the optical path.
  • the optical signal from at least a part of the display area of the display screen 120 is guided to the optical fingerprint module 130, so that the fingerprint detection area 103 is actually located in the display area of the display screen 120.
  • the area of the fingerprint detection area 103 may be different from the area of the sensing array 133 of the optical fingerprint module 130, such as an optical path design for imaging through a lens, a reflective folding optical path design, or other optical path designs such as light convergence or reflection. , So that the area of the fingerprint detection area 103 of the optical fingerprint module 130 is larger than the area of the sensing array 133 of the optical fingerprint module 130.
  • the fingerprint detection area 103 of the optical fingerprint module 130 can also be designed to be substantially equal to the area of the sensing array 133 of the optical fingerprint module 130. Unanimous.
  • the electronic device 10 adopting the above structure does not need to reserve space on the front side to set a fingerprint button (such as the Home button), so that a full-screen solution can be adopted, that is, the display area of the display screen 120 It can be basically extended to the front of the entire electronic device 10.
  • a fingerprint button such as the Home button
  • the optical fingerprint module 130 includes a light detecting part 134 and an optical component 132.
  • the light detection part 134 includes the sensor array 133, a reading circuit electrically connected to the sensor array 133, and other auxiliary circuits, which can be fabricated on a chip (Die) by a semiconductor process to form an optical fingerprint chip or Optical fingerprint sensor, also called sensor chip or chip, etc.
  • the sensing array 133 is specifically a photodetector (Photodetector) array, which includes a plurality of photodetectors distributed in an array, and the photodetectors can be used as the above-mentioned optical sensing unit.
  • the optical component 132 may be disposed above the sensing array 133 of the light detecting part 134, and it may specifically include a filter layer (Filter), a light guide layer or a light path guiding structure, and other optical elements. It can be used to filter out the ambient light penetrating the finger, and the light guide layer is mainly used to guide the reflected light reflected from the surface of the finger to the sensing array 133 for optical detection.
  • a filter layer Finter
  • a light guide layer or a light path guiding structure and other optical elements. It can be used to filter out the ambient light penetrating the finger, and the light guide layer is mainly used to guide the reflected light reflected from the surface of the finger to the sensing array 133 for optical detection.
  • the optical assembly 132 and the light detecting part 134 may be packaged in the same optical fingerprint component.
  • the optical component 132 and the optical detection part 134 may be packaged in the same optical fingerprint chip, or the optical component 132 may be arranged outside the chip where the optical detection part 134 is located, for example, the optical component 132 is attached above the chip, or some components of the optical assembly 132 are integrated into the chip.
  • the light guide layer of the optical component 132 has multiple implementation schemes.
  • the light guide layer may specifically be a collimator (Collimator) layer fabricated on a semiconductor silicon wafer, which has a plurality of collimator units or a micro-hole array, and the collimator unit may be specifically small holes, from Among the reflected light reflected by the finger, the light incident perpendicularly to the collimating unit can pass through and be received by the optical sensing unit below it, while the light with an excessively large incident angle is reflected in the collimating unit multiple times.
  • each optical sensing unit can basically only receive the reflected light reflected by the fingerprint lines directly above it, so that the sensing array 133 can detect the fingerprint image of the finger.
  • the light guide layer may also be an optical lens (Lens) layer, which has one or more lens units, such as a lens group composed of one or more aspheric lenses, which is used to The reflected light reflected from the finger is condensed to the sensing array 133 of the light detection part 134 below it, so that the sensing array 133 can perform imaging based on the reflected light, thereby obtaining a fingerprint image of the finger.
  • the optical lens layer may further have a pinhole formed in the optical path of the lens unit, and the pinhole may cooperate with the optical lens layer to expand the field of view of the optical fingerprint module 130 to improve The fingerprint imaging effect of the optical fingerprint module 130 is described.
  • the light guide layer may also specifically adopt a micro-lens (Micro-Lens) layer.
  • the micro-lens layer has a micro-lens array formed by a plurality of micro-lens, which may be obtained through a semiconductor growth process or other processes. It is formed above the sensing array 133 of the light detecting part 134, and each microlens may correspond to one of the sensing units of the sensing array 133, respectively.
  • Another optical film layer such as a dielectric layer or a passivation layer, may also be formed between the micro lens layer and the sensing unit.
  • a light blocking layer (or called a light blocking layer, a light blocking layer, etc.) with micro-holes may also be included between the micro-lens layer and the sensing unit, wherein the micro-holes are formed in the corresponding micro-lens.
  • the light blocking layer can block the optical interference between the adjacent microlens and the sensor unit, and make the light corresponding to the sensor unit converge into the microhole through the microlens, and It is transmitted to the sensing unit via the micro-hole for optical fingerprint imaging.
  • a micro lens layer may be further provided above or below the collimator layer or the optical lens layer.
  • the collimator layer or the optical lens layer is used in combination with the microlens layer, its specific laminated structure or optical path may need to be adjusted according to actual needs.
  • the display screen 120 may be a display screen with a self-luminous display unit, such as an organic light-emitting diode (Organic Light-Emitting Diode, OLED) display or a micro-LED (Micro-LED) display Screen.
  • OLED Organic Light-Emitting Diode
  • Micro-LED Micro-LED
  • the optical fingerprint module 130 can use the display unit (ie, an OLED light source) of the OLED display screen 120 located in the fingerprint detection area 103 as an excitation light source for optical fingerprint detection.
  • the display screen 120 emits a beam of light 111 to the finger 140 above the fingerprint detection area 103.
  • the light 111 is reflected on the surface of the finger 140 to form reflected light or pass through all the fingers.
  • the finger 140 scatters inside to form scattered light.
  • the above-mentioned reflected light and scattered light are also collectively referred to as reflected light. Since the ridge 141 and valley 142 of the fingerprint have different light reflection capabilities, the reflected light 151 from the fingerprint ridge and the reflected light 152 from the fingerprint valley have different light intensities, and the reflected light passes through the optical component 132 Then, it is received by the sensing array 133 in the optical fingerprint module 130 and converted into a corresponding electrical signal, that is, a fingerprint detection signal. Based on the fingerprint detection signal, fingerprint image data can be obtained, and fingerprint matching verification can be further performed, thereby implementing an optical fingerprint recognition function in the electronic device 10.
  • the optical fingerprint module 130 may also use a built-in light source or an external light source to provide an optical signal for fingerprint detection.
  • the optical fingerprint module 130 may be suitable for non-self-luminous display screens, such as liquid crystal display screens or other passively-luminous display screens.
  • the optical fingerprint system of the electronic device 10 may also include an excitation light source for optical fingerprint detection.
  • the excitation light source may specifically be an infrared light source or a light source of non-visible light of a specific wavelength, which may be arranged under the backlight module of the liquid crystal display or arranged in the edge area under the protective cover of the electronic device 10, and the The optical fingerprint module 130 can be arranged under the edge area of the liquid crystal panel or the protective cover and guided by the light path so that the fingerprint detection light can reach the optical fingerprint module 130; or, the optical fingerprint module 130 can also be arranged in all areas. Below the backlight module, and the backlight module is designed to allow the fingerprint detection light to pass through the liquid crystal panel and the backlight module and reach the optical Fingerprint module 130.
  • the optical fingerprint module 130 adopts a built-in light source or an external light source to provide an optical signal for fingerprint detection, the detection principle is the same as that described above.
  • the electronic device 10 may also include a transparent protective cover, and the cover may be a glass cover or a sapphire cover, which is located above the display screen 120 and covers the electronic device.
  • the front of 10. Therefore, in the embodiments of the present application, the so-called finger pressing on the display screen 120 actually refers to pressing on the cover plate above the display screen 120 or covering the surface of the protective layer of the cover plate.
  • the electronic device 10 may further include a circuit board 150, and the circuit board 150 is disposed under the optical fingerprint module 130.
  • the optical fingerprint module 130 can be adhered to the circuit board 150 through adhesive, and is electrically connected to the circuit board 150 through soldering pads and metal wires.
  • the optical fingerprint module 130 can realize electrical interconnection and signal transmission with other peripheral circuits or other components of the electronic device 10 through the circuit board 150.
  • the optical fingerprint module 130 may receive the control signal of the processing unit of the electronic device 10 through the circuit board 150, and may also output the fingerprint detection signal from the optical fingerprint module 130 to the processing unit of the terminal device 10 through the circuit board 150. Control unit, etc.
  • the optical fingerprint module 130 may include only one optical fingerprint sensor. At this time, the fingerprint detection area 103 of the optical fingerprint module 130 has a small area and a fixed position. Therefore, the user needs to input fingerprints. Press the finger to a specific position of the fingerprint detection area 103, otherwise the optical fingerprint module 130 may not be able to collect fingerprint images, resulting in poor user experience.
  • the optical fingerprint module 130 may include multiple optical fingerprint sensors. The multiple optical fingerprint sensors may be arranged side by side under the display screen 120 in a splicing manner, and the sensing areas of the multiple optical fingerprint sensors collectively constitute the fingerprint detection area 103 of the optical fingerprint module 130.
  • the fingerprint detection area 103 of the optical fingerprint module 130 can be extended to the main area of the lower half of the display screen, that is, to the area where the finger is habitually pressed, so as to realize the blind fingerprint input operation. Further, when the number of optical fingerprint sensors is sufficient, the fingerprint detection area 103 can also be extended to half of the display area or even the entire display area, thereby realizing half-screen or full-screen fingerprint detection.
  • the optical fingerprint module 130 in the electronic device 10 includes a plurality of optical fingerprint sensors, and the plurality of optical fingerprint sensors may be arranged side by side in a manner such as splicing. Below the display screen 120 and the sensing areas of the multiple optical fingerprint sensors collectively constitute the fingerprint detection area 103 of the optical fingerprint module 130.
  • the optical component 132 may include multiple light guide layers, and each light guide layer corresponds to an optical fingerprint sensor, and is attached to the optical fingerprint sensor. It is arranged above the corresponding optical fingerprint sensor.
  • the plurality of optical fingerprint sensors may also share an integral light guide layer, that is, the light guide layer has an area large enough to cover the sensing array of the plurality of optical fingerprint sensors.
  • the optical component 132 may also include other optical elements, such as a filter layer (Filter) or other optical films, which may be arranged between the light guide layer and the optical fingerprint sensor, or may be arranged on the optical fingerprint sensor.
  • the display screen 120 and the light guide layer are mainly used to isolate the influence of external interference light on the optical fingerprint detection.
  • the filter can be used to filter out the ambient light that penetrates the finger and enters the optical fingerprint sensor through the display screen 120.
  • the optical filter may be separately provided for each optical fingerprint sensor to filter out interference light, or a large-area optical filter may be used to simultaneously cover the multiple optical fingerprint sensors.
  • the light guide layer may also be replaced by an optical lens (Lens), and a small hole formed by a light-shielding material above the optical lens can cooperate with the optical lens to converge fingerprint detection light to an optical fingerprint sensor below to realize fingerprint imaging.
  • each optical fingerprint sensor may be configured with an optical lens to perform fingerprint imaging, or the multiple optical fingerprint sensors may also use the same optical lens to achieve light convergence and fingerprint imaging.
  • each optical fingerprint sensor may even have two sensing arrays (Dual Array) or multiple sensing arrays (Multi-Array), and two or more optical lenses are configured to cooperate with the two at the same time. Or multiple sensing arrays perform optical imaging, thereby reducing the imaging distance and enhancing the imaging effect.
  • the light source illuminates the finger above the display screen, and the optical fingerprint sensor collects the light signal returned by the reflection or scattering of the finger, so as to obtain the fingerprint information of the finger.
  • red light and infrared light can interfere with fingerprint detection.
  • the red light and infrared light in the sunlight can directly pass through the finger to reach the optical fingerprint sensor, so that the light carrying the fingerprint signal is submerged in the background noise of red light and infrared light, which affects the optics.
  • the performance of fingerprint detection under the screen is performed outdoors.
  • a filter can be set on the optical path between the display screen and the optical fingerprint sensor to filter out the red light and infrared light.
  • the filter can cut off the red light and infrared light in the wavelength band above 600nm, and reduce the red light and infrared light entering the optical fingerprint sensor through outward reflection, thereby weakening the interference of red light and infrared light on useful fingerprint detection signals .
  • the reflected red light will cause visible "erythema" in the fingerprint detection area of the display screen, which affects the appearance of the display screen and reduces the user experience.
  • the optical filter of the embodiments of the present application can be integrated with the optical fingerprint sensor, or can be installed independently of the optical fingerprint sensor, and can be installed at any position between the display screen and the optical fingerprint sensor, for example, on the light guide layer. Above.
  • the filter When the filter is arranged independently of the optical fingerprint sensor, it is necessary to ensure the structural stability of the filter to avoid “warping" of the filter film.
  • the embodiments of the present application provide a filter, which can effectively filter non-target optical signals, improve the performance of fingerprint recognition, and avoid the occurrence of "erythema" without affecting the appearance of the display screen. , At the same time, it has good structural stability.
  • Figures 3 and 4 show schematic diagrams of a possible filter.
  • the upper surface of the substrate 400 is covered with an anti-reflective (Anti-Reflective Coating, AR) film 401 (also called anti-reflective coating or anti-reflective anti-reflective coating), which is used to increase the penetration of the filter. Reduce the reflected light signal.
  • AR Anti-Reflective Coating
  • the lower surface of the substrate 400 is sequentially covered with an ultraviolet (UV) film layer 402 and an infrared (IR) film layer 403, wherein the cut-off wavelength of the UV film layer 402 can be, for example, between 400 nm and 420 nm for reflection Excluding the violet light and ultraviolet light in the wavelength band below its cut-off wavelength, the cut-off wavelength of the IR film 403 is, for example, between 600 nm and 620 nm, and is used to reflect the red light and infrared light in the wavelength band above the cut-off wavelength.
  • UV ultraviolet
  • IR infrared
  • the UV film layer 402 may be disposed on the upper surface of the substrate 400
  • the AR film layer 401 is disposed on the upper surface of the UV film layer 402
  • the IR film layer 403 is disposed on the lower surface of the substrate.
  • the AR film 401 is a non-essential film, and is usually used in scenarios where there is a high demand for transmittance.
  • the implementation of this application has made further improvements to the filter, which does not affect the user's visual experience while ensuring the fingerprint detection performance, and has good structural stability.
  • FIG. 5 is a schematic block diagram of a filter 500 according to an embodiment of the present application.
  • the filter 500 is arranged between the display screen and the optical fingerprint sensor, the optical fingerprint sensor is used to detect the light signal returned by the finger above the display screen, and the filter 500 is used to filter the light signal The optical signal transmitted to the non-target wavelength band in the optical path of the optical fingerprint sensor.
  • the filter includes:
  • At least one cut-off film layer 520 for reflecting the optical signal of the non-target waveband At least one cut-off film layer 520 for reflecting the optical signal of the non-target waveband.
  • At least one absorbing layer 530 is used to absorb the optical signal in the non-target wavelength band.
  • the at least one cut-off film layer 520 is located on both sides of the substrate 510.
  • the optical signal in the non-target waveband includes the optical signal in the red waveband and the optical signal in the infrared waveband.
  • the wavelength of the optical signal in the red wavelength band is, for example, between 620 nanometers and 770 nanometers, which is also referred to as red light below; the wavelength of the optical signal in the infrared wavelength band is, for example, between 770 nanometers and 1000 nanometers, which is also referred to as Infrared light.
  • the optical signal in the non-target wavelength band may also include an optical signal in the purple light band and an optical signal in the ultraviolet wavelength band, which are also referred to as purple light and ultraviolet light hereinafter, respectively.
  • the substrate 510 may be, for example, a glass substrate or a resin substrate.
  • the light transmittance of the substrate 510 to light signals with a wavelength of 450-600 nanometers is, for example, 80%-90%.
  • the at least one cutoff film layer 520 may include an IR film layer and/or a UV film layer.
  • the at least one cut-off film layer 520 may be formed by sputtering, plating, or deposition, for example.
  • the cut-off wavelength of the IR film layer can be located between 620-680 nanometers, for example, which can reflect light in the wavelength band above the cut-off wavelength, so that the optical signal of this wavelength band will not be collected by the optical fingerprint sensor, and red light and red light can be avoided. Infrared light affects the useful fingerprint detection signal.
  • the cut-off wavelength of the UV film layer may be between 400-420 nanometers, for example, and can reflect light in the wavelength band below the cut-off wavelength, so that violet light and ultraviolet light are not collected by the optical fingerprint sensor.
  • the organic material layers in the light path such as the microlens array, the IR film layer and the absorption layer in the filter 500, etc., are likely to age, so A UV film layer can be added to the filter 500; on the other hand, the UV film layer can be used to balance the IR film layer.
  • the substrate 510 can be made The film layer stress on both sides is balanced, avoiding the film "warping" caused by uneven stress, and improving the structural stability of the filter.
  • the at least one absorption layer 530 includes an ink layer and/or a cyan paint layer.
  • the ink layer and the cyan paint layer can be formed by spin coating or the like, for example.
  • the ink layer and the cyan paint layer can be used to absorb red light and infrared light, but the material properties of the two are different.
  • the ink is likely to have poor light absorption performance due to oxidation and other reasons. Therefore, in the embodiment of the present application, preferably, the ink layer is coated on the upper surface and/or the lower surface of the substrate 510. Further, a cut-off film layer is made on the outer side of the ink layer, and the cut-off film layer can be used to reflect off non-target wavelength light, and can protect the ink layer on the outer side of the ink layer.
  • the upper surface of the substrate 510 is covered with the UV film layer, and the lower surface of the substrate 510 is sequentially covered with the ink layer and the IR film layer.
  • the upper surface of the substrate 510 is sequentially covered with the ink layer and the UV film layer, and the lower surface of the substrate 510 is covered with the IR film layer.
  • the upper surface of the substrate 510 is sequentially covered with the ink layer and the UV film layer, and the lower surface of the substrate 510 is sequentially covered with the ink layer and the IR film layer.
  • the cyan paint layer has a good ability to absorb red light. Based on the three primary colors of light, the combination of blue and green is cyan. Cyan does not contain red light. Red and cyan are complementary colors and can absorb each other’s colors. Therefore, the use of cyan paint to absorb red light has a good effect.
  • the cyan paint layer is susceptible to current, temperature, etc. When the IR film and UV film are plated, the high temperature environment may cause the properties of the cyan paint to change and affect its light absorption performance. Therefore, in the embodiments of the present application, preferably, the cyan paint layer is located on the outermost side of the filter. When making the filter, after the other film layers on both sides of the substrate are finished, the cyan paint layer is applied.
  • the upper surface of the substrate 510 is sequentially covered with the UV film layer and the cyan paint layer, and the lower surface of the substrate 510 is covered with the IR film layer.
  • the upper surface of the substrate 510 is covered with the UV film layer, and the lower surface covering the substrate 510 is sequentially covered with the IR film layer and the cyan paint layer.
  • the upper surface of the substrate 510 is sequentially covered with the UV film layer and the cyan paint layer, and the lower surface of the substrate 510 is sequentially covered with the IR film layer and the cyan paint layer.
  • the ink layer and cyan paint layer are mainly used to absorb red light, because red light is visible light, which will make the fingerprint detection area on the display screen show "erythema" visible to the naked eye.
  • the infrared light is invisible light, so it will not have a major impact on the appearance of the display screen.
  • the ink layer and the cyan paint layer can also be used to absorb a part of infrared light, such as near-infrared light, so as to enhance the ability of the filter 500 to filter red light and infrared light.
  • the half-wave T50, that is, the wavelength corresponding to the transmittance of 50%
  • T50 that is, the wavelength corresponding to the transmittance of 50%
  • At least one absorption layer 530 includes one or more ink layers.
  • at least one absorption layer 530 includes one or more cyan paint layers.
  • the upper surface of the substrate 510 is covered with a UV film layer 521, which can be fabricated on the upper surface of the substrate 510 by, for example, sputtering, evaporation, or deposition.
  • the cut-off wavelength of the UV film layer 521 may be between 400-420 nanometers, and is used to reflect the violet light and ultraviolet light outward to prevent the violet light and ultraviolet light from reaching the optical fingerprint sensor.
  • the lower surface of the substrate 510 is coated with an ink layer 5311 for absorbing light signals in the red wavelength band.
  • the lower surface of the ink layer 5311 is the IR film layer 522, which can be formed on the lower surface of the ink layer 5311 by, for example, sputtering, evaporation, or deposition.
  • the cut-off wavelength of the IR film layer 522 may be between 620-680 nanometers, and is used to reflect the red light and the infrared light outward to prevent the red light and the infrared light from being transmitted to the optical fingerprint sensor
  • the ink layer 5311 may be located on the lower surface of the substrate 510 as shown in FIG. 6.
  • the ink layer 5311 may also be located on the upper surface of the substrate 510, as shown in FIG. 7 for example.
  • the ink layer 5311 is coated on the upper surface of the substrate 510, and the UV film layer 521 is plated on the upper surface of the ink layer 5311.
  • the IR film 522 is plated on the lower surface of the substrate 510.
  • both the lower surface and the upper surface of the substrate 510 can be formed with ink layers.
  • the upper surface and the lower surface of the substrate 510 are respectively coated with an ink layer 5311 and an ink layer 5312 for absorbing light signals in the red wavelength band.
  • a UV film layer 521 is plated on the upper surface of the ink layer 5311 to filter out violet light and ultraviolet light.
  • an IR film layer 522 is plated on the lower surface of the ink layer 5312, so as to achieve filtering of red light and infrared light.
  • the ink layer is coated on the upper surface and/or the lower surface of the substrate, and the UV film layer and the IR film layer cover the outer surface of the ink layer, so that the ink layer can be protected.
  • the upper surface of the substrate 510 is covered with a UV film layer 521, which can be fabricated on the upper surface of the substrate 510 by, for example, sputtering, evaporation or deposition.
  • the cut-off wavelength of the UV film layer 521 may be between 400-420 nanometers, and is used to reflect the violet light and ultraviolet light outward to prevent the violet light and ultraviolet light from reaching the optical fingerprint sensor.
  • the upper surface of the UV film layer 521 is coated with a cyan paint layer 5321 for absorbing light signals in the red wavelength band.
  • the lower surface of the substrate 510 is plated with an IR film layer 522, which can be fabricated on the lower surface of the substrate 510 by, for example, sputtering, evaporation, or deposition.
  • the cut-off wavelength of the IR film layer 522 may be between 620-680 nanometers, and is used to reflect the red light and the infrared light outward to prevent the red light and the infrared light from being transmitted to the optical fingerprint sensor.
  • the cyan paint layer 5321 may be located on the upper side of the substrate 510 as shown in FIG. 9.
  • the cyan paint layer 5321 may also be located on the underside of the substrate 510, as shown in FIG. 10, for example.
  • the IR film layer 522 is plated on the lower surface of the substrate 510, and the cyan paint layer 5321 is coated on the lower surface of the IR film layer 522.
  • the UV film 521 is plated on the upper surface of the substrate 510.
  • both the lower side and the upper side of the substrate 510 may be provided with a cyan paint layer.
  • the upper surface and the lower surface of the substrate 510 are respectively plated with a UV film layer 521 and an IR film layer 522 for filtering violet light and ultraviolet light, as well as red light and infrared light.
  • the upper surface of the UV film layer 521 is coated with a cyan paint layer 5321.
  • the lower surface of the IR film layer 522 is coated with a cyan paint layer 5322.
  • the cyan paint layer 5321 and the cyan paint layer 5322 can be used to filter red light and infrared light.
  • the cyan paint layer is coated on the outside of the UV film layer and the IR film layer.
  • the UV film layer and the IR film layer can be plated on the upper surface and the lower surface of the substrate first, and the cyan paint layer is coated on the outside of the UV film and/or IR film.
  • the UV film layer and the IR film layer can be plated under a high-temperature process, and when the cyan paint layer is applied later, it will not be affected by processes such as the coating temperature.
  • the above-mentioned UV film layer 521 and IR film layer 522 may be plated on both sides of the base 510 respectively, or may be plated on the same side of the base 510.
  • the UV film layer 521 when the UV film layer 521 is disposed on the upper side of the substrate 510 and the IR film layer 522 is disposed on the lower side of the substrate, it can not only avoid the "warpage" of the film caused by the uneven stress on both sides of the substrate, but also can preferentially filter In addition to the high-energy violet light and ultraviolet light, the IR film layer 522 is prevented from being damaged. For example, as shown in FIG.
  • the UV film layer 521 is plated on the upper surface of the substrate 510, and the ink layer 5311 and the IR film layer 522 are respectively located on the lower surface of the substrate 510, so the light incident on the filter 500 first passes through the UV film layer 521, so that the purple light and ultraviolet light components in the light reaching the ink layer 5311 and the IR film layer 522 are significantly reduced.
  • the filter 500 when the filter 500 is disposed above the microlens array, it can also prevent long-term irradiation of violet light and ultraviolet light from affecting the microlens array.
  • the microlens array is also a layer of polymer organic film.
  • the ink layer is located above the IR film layer 522.
  • the light incident on the filter from above first reaches the UV film layer 521, so that violet light and ultraviolet light Is filtered out.
  • the remaining light enters the ink layer 5311, and red light and infrared light therein can be absorbed by the ink layer 5311.
  • the red light and infrared light that are not absorbed by the ink layer 5311 reach the IR film layer 522 and are thus reflected by the IR film layer 522.
  • the red light and infrared light reflected by the IR film layer 522 can be secondary absorbed by the ink layer 5311 above the IR film layer 522.
  • the light of the target waveband passes through the IR film 522 to reach the optical fingerprint sensor.
  • the red light and infrared light are reflected by the IR film layer 522, but the red light and infrared light are absorbed by the ink layer 5311, so that the red light and infrared light will neither interfere with the fingerprint detection signal nor
  • the "erythema" appears on the display screen and affects the user's visual experience, so as to achieve a good balance between the performance and appearance of optical fingerprint detection.
  • the cyan paint layer is located above the IR film layer 522.
  • the light incident on the filter from above first reaches the cyan paint layer 5321, and the red light and infrared light therein can be absorbed by the cyan paint layer 5321.
  • the remaining light enters the UV film layer 521 to further filter out the violet light and ultraviolet light.
  • the red light and infrared light that are not absorbed by the ink layer 5311 then pass through the substrate 510 to reach the IR film layer 522, and are thus reflected by the IR film layer 522.
  • the red light and infrared light reflected by the IR film layer 522 can be secondarily absorbed by the cyan paint layer 5321 above the IR film layer 522.
  • the light of the target waveband passes through the IR film 522 to reach the optical fingerprint sensor.
  • the red light and infrared light are reflected by the IR film layer 522, but the red light and infrared light are absorbed by the cyan paint layer 5321, so that the red light and infrared light will not interfere with the fingerprint detection signal, nor It will show "erythema" on the display screen and affect the user's visual experience, so as to achieve a good balance between the performance and appearance of optical fingerprint detection.
  • the present application does not limit the vertical positional relationship between the absorption layer and the IR film layer.
  • the absorbing layer can also be located under the IR film layer. Taking the absorption layer as a cyan paint layer as an example, as shown in FIG. 10, the cutoff wavelength of the IR film layer can be set to be larger, for example, 680 nanometers. In this way, when the light passing through the UV film 511 reaches the IR film layer 522, the red light and infrared light above 680 nanometers are reflected back by the IR film layer 522, and the remaining red light reaches the cyan paint layer 5321 under the IR film layer 522. absorbed.
  • the IR film layer 522 can be arranged above the cyan paint layer 5321, so that the cyan paint layer 5321 covers the outside of the IR film layer 522 to avoid the manufacturing process. It affects the light absorption performance of the cyan paint layer 5321.
  • the filter may include one ink layer or multiple ink layers.
  • the ink layer can be located above the IR film layer, as shown in Figures 6 and 7; the ink layer can also be located below the IR film layer, and when the ink layer is below the IR film layer, the cutoff wavelength of the IR film layer You can set a larger value; or, set two ink layers on both sides of the substrate, for example, as shown in Figure 8.
  • the filter may also include one cyan paint layer or multiple cyan paint layers.
  • the cyan paint layer can be located above the IR film layer, as shown in Figure 9; the cyan paint layer can also be located below the IR film layer, as shown in Figure 10, and when the cyan paint layer is below the IR film layer,
  • the cut-off wavelength of the IR film layer can be set to a larger value; alternatively, two cyan paint layers are provided on both sides of the substrate, for example, as shown in FIG. 11.
  • the ink layer and the cyan paint layer can also be used in the filter at the same time to achieve a better light absorption effect.
  • the positions of the above-mentioned different absorption layers and the number of coating layers can be adjusted according to the actual situation, so as to meet the requirements of appearance requirements and fingerprint detection performance.
  • the filter 500 may also include other film layers, such as AR film layers.
  • the AR film layer is used to increase the transmittance of the filter 500 to light in the target wavelength band.
  • an AR film layer may be provided in the filter 500.
  • the AR film layer can also be used to balance other film layers, such as IR film layers, so as to balance the film layer stress on both sides of the substrate 510 and avoid "warping" of the film layer caused by uneven stress.
  • the embodiments of the present application do not limit the number of coating layers of the cut-off film layer and the thickness of the absorption layer.
  • the number of coating layers of at least one cutoff film layer 520 is between 10-80.
  • the sum of the coating layers of the UV film layer and the IR film layer is between 10-80 layers.
  • the thickness of the at least one absorption layer 530 is between 1-30 microns.
  • the total thickness of the ink layer or the total thickness of the cyan paint layer is between 1-30 microns.
  • the optical filter can be used as a relatively independent component from the optical fingerprint sensor, and can be arranged at any position in the optical path from the display screen to the optical fingerprint sensor to filter the optical signal returned by the finger. In this way, the optical signal in the non-target waveband is filtered out, so that the optical signal in the target waveband reaches the optical fingerprint sensor.
  • the filter is disposed between the display screen and the light guide layer, and the light guide layer is used to converge the optical signal of the target wavelength band after passing through the filter to the optical fingerprint sensor.
  • the light guide layer may include an optical collimator, a lens, or a micro lens array.
  • an optical collimator for the specific details of the optical collimator, lens, or microlens array, reference may be made to the related descriptions in FIG. 1B and FIG. 2B. For the sake of brevity, details are not repeated here.
  • the filter 500 is disposed above the micro lens array 610.
  • the space between the filter 500 and the microlens array 610 can be air, or a light-transmitting medium can be filled.
  • a light-shielding material can be provided around the micro lens array 610.
  • a light blocking layer 620, a light blocking layer 630, and an optical fingerprint sensor 710 are sequentially arranged below the microlens array 600.
  • the microlens array 610, the light blocking layer 620, the light blocking layer 630 and the optical fingerprint sensor 710 may be filled with a light-transmitting medium.
  • the micro lens array 610 is used to converge the light signal returned by the finger above the display screen.
  • Both the light blocking layer 620 and the light blocking layer 630 are provided with openings corresponding to the respective microlenses.
  • the light signal condensed by each microlens passes through the light blocking layer 620 and the opening corresponding to the microlens in the light blocking layer 630 in turn, and reaches the sensing unit of the optical fingerprint sensor 710.
  • the light condensed by the microlens 611 sequentially passes through the opening 621 on the light blocking layer 620 and the opening 631 on the light blocking layer 630 to reach the sensing unit 711.
  • the embodiment of the present application also provides a fingerprint detection device.
  • the device 1300 includes: an optical fingerprint sensor 1310 and the filter 500 in the foregoing various embodiments of the present application.
  • the optical filter 500 is used to transmit the optical signal in the target wavelength band among the optical signals returned by the finger to the optical fingerprint sensor 1310.
  • An embodiment of the present application also provides an electronic device, which includes a display screen and the fingerprint detection device 1300 in the foregoing various embodiments of the present application.
  • the display screen may be an ordinary non-folding display screen, or may be a foldable display screen or called a flexible display screen.
  • the electronic devices in the embodiments of the present application may be portable or mobile computing devices such as terminal devices, mobile phones, tablet computers, notebook computers, desktop computers, game devices, in-vehicle electronic devices or wearable smart devices, and Electronic databases, automobiles, bank automated teller machines (Automated Teller Machine, ATM) and other electronic equipment.
  • the wearable smart device includes full-featured, large-sized, complete or partial functions that can be realized without relying on smart phones, such as smart watches or smart glasses, etc., and only focus on a certain type of application function, and need to cooperate with other devices such as smart phones. Use, such as various types of smart bracelets, smart jewelry and other equipment for physical sign monitoring.

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Abstract

本申请提供一种滤光片，在保证指纹检测性能的同时不会对用户视觉感受带来影响，并具有良好的结构稳定性。所述滤光片设置于显示屏与光学指纹传感器之间，所述光学指纹传感器用于检测所述显示屏上方的手指返回的光信号，所述滤光片用于过滤所述光信号传输至所述光学指纹传感器的光路中的非目标波段的光信号，所述非目标波段的光信号包括红光波段的光信号和红外波段的光信号，所述滤光片包括：基底；至少一个截止膜层，用于反射所述非目标波段的光信号，其中，所述至少一个截止膜层位于在所述基底的两侧；以及，至少一个涂层，用于吸收所述非目标波段的光信号。

Description

滤光片、指纹检测的装置和电子设备 技术领域
本申请实施例涉及生物特征识别领域，并且更具体地，涉及一种滤光片、指纹检测的装置和电子设备。
背景技术
光学指纹模组采集光线在手指上发生反射或透射而返回的光线，并根据光线中携带的手指的指纹信息，实现光学屏下指纹识别。但是，在进行指纹检测时，非目标波段的光线例如红光波段和红外波段的光线，会对屏下光学指纹检测造成干扰。例如，在室外进行指纹检测时，太阳光中的红光和红外光可以直接透过手指到达光学指纹模组，使得携带指纹信号的光线湮没在红光和红外光的背景噪声之中，影响了光学屏下指纹检测的性能。
发明内容
本申请实施例提供一种滤光片、指纹检测的装置和电子设备，在保证指纹检测性能的同时不会影响用户的视觉感受，并具有良好的结构稳定性。
第一方面，提供了一种滤光片，所述滤光片设置于显示屏与光学指纹传感器之间，所述光学指纹传感器用于检测所述显示屏上方的手指返回的光信号，所述滤光片用于过滤所述光信号传输至所述光学指纹传感器的光路中的非目标波段的光信号，所述非目标波段的光信号包括红光波段的光信号和红外波段的光信号，所述滤光片包括：基底；至少一个截止膜层，用于反射所述非目标波段的光信号，其中，所述至少一个截止膜层位于在所述基底的两侧；以及，至少一个吸收层，用于吸收所述非目标波段的光信号。
在一种可能的实现方式中，所述至少一个吸收层包括油墨层和/或青色涂料层。
在一种可能的实现方式中，所述至少一个截止膜层包括IR膜层和/或UV膜层。
在一种可能的实现方式中，所述红光IR膜层的截止波长位于620纳米至680纳米之间。
在一种可能的实现方式中，所述紫光UV膜层的截止波长位于400纳米 至420纳米之间。
在一种可能的实现方式中，所述至少一个吸收层包括油墨层，其中，所述油墨层涂覆在所述基底的上表面和/或下表面。
在一种可能的实现方式中，所述基底的上表面覆盖有所述UV膜层，所述基底的下表面依次覆盖有所述油墨层和所述IR膜层。
在一种可能的实现方式中，所述基底的上表面依次覆盖有所述油墨层和所述UV膜层，所述基底的下表面覆盖有所述IR膜层。
在一种可能的实现方式中，所述基底的上表面依次覆盖有所述油墨层和所述UV膜层，所述基底的下表面依次覆盖有所述油墨层和所述IR膜层。
在一种可能的实现方式中，所述至少一个吸收层包括青色涂料层，其中，所述青色涂料层位于所述滤光片的最外侧。
在一种可能的实现方式中，所述基底的上表面依次覆盖有所述UV膜层和所述青色涂料层，所述基底的下表面覆盖有所述IR膜层。
在一种可能的实现方式中，所述基底的上表面覆盖有所述UV膜层，覆盖于所述基底的下表面依次覆盖有所述IR膜层和所述青色涂料层。
在一种可能的实现方式中，所述基底的上表面依次覆盖有所述UV膜层和所述青色涂料层，所述基底的下表面依次覆盖有所述IR膜层和所述青色涂料层。
在一种可能的实现方式中，所述非目标波段中红光波段的光信号的波长位于620纳米至770纳米之间，所述非目标波段中红外波段的光信号的波长位于770纳米至1000纳米之间。
在一种可能的实现方式中，所述至少一个截止膜层的镀膜层数位于10-80之间。
在一种可能的实现方式中，所述至少一个吸收层的厚度位于1-30微米之间。
在一种可能的实现方式中，所述多个滤光片还包括：AR膜层，用于提高所述滤光片对目标波段的光线的透过率。
在一种可能的实现方式中，所述基底为玻璃或树脂。
在一种可能的实现方式中，所述基底对波长为450纳米至600纳米的光信号的透光率为80％-90％。
在一种可能的实现方式中，所述至少一个截止膜层通过溅射、镀膜或沉 积的方式形成。
在一种可能的实现方式中，所述滤光片设置在所述显示屏与导光层之间，所述导光层用于将经过所述滤光片之后的目标波段的光信号会聚至所述光学指纹传感器。
在一种可能的实现方式中，所述导光层包括光学准直器、镜头、或者微透镜阵列。
第二方面，提供了一种指纹检测的装置，所述装置包括：
光学指纹传感器；以及，
第一方面或第一方面的任意可能的实现方式中的滤光片。
第三方面，提供了一种电子设备，包括：
显示屏；以及，
第二方面或第二方面的任意可能的实现方式中的指纹检测的装置。
基于上述技术方案，通过在基底两侧设置能够吸收红光和红外光的吸收层以及使红光和红外光截止的截止膜层，减小了红光和红外光对指纹检测性能的影响，并且由于吸收层对红光的吸收，避免了显示屏上呈现明显的“红斑”，在保证指纹检测性能的同时不影响用户的视觉感受。另外，由于各个截止膜层可以合理地设置在基底的两侧，该滤光片不易发生应力不均导致的膜层“翘曲”现象，具有良好的结构稳定性。
附图说明
图1A和图2A是本申请可以适用的电子设备的示意图。
图1B和图2B分别是图1A和图2A所示的电子设备沿A-A’方向的剖面示意图。
图3是一种可能的滤光片的结构示意图。
图4是一种可能的滤光片的结构示意图。
图5是本申请实施例的滤光片的示意性框图。
图6是基于图5所示的滤光片的一种可能的实现方式。
图7是基于图5所示的滤光片的一种可能的实现方式。
图8是基于图5所示的滤光片的一种可能的实现方式。
图9是基于图5所示的滤光片的一种可能的实现方式。
图10是基于图5所示的滤光片的一种可能的实现方式。
图11是基于图5所示的滤光片的一种可能的实现方式。
图12是本申请实施例的指纹检测的装置的示意性结构图。
图13是本申请实施例的指纹检测的装置的示意性框图。
具体实施方式
下面将结合附图，对本申请中的技术方案进行描述。
应理解，本申请实施例可以应用于指纹系统，包括但不限于光学、超声波或其他指纹识别系统和基于光学、超声波或其他指纹成像的医疗诊断产品，本申请实施例仅以光学指纹系统为例进行说明，但不应对本申请实施例构成任何限定，本申请实施例同样适用于其他采用光学、超声波或其他成像技术的系统等。
作为一种常见的应用场景，本申请实施例提供的光学指纹系统可以应用在智能手机、平板电脑以及其他具有显示屏的移动终端或者其他电子设备；更具体地，在上述电子设备中，光学指纹模组可以设置在显示屏下方的局部区域或者全部区域，从而形成屏下(Under-display或Under-screen)光学指纹系统。或者，所述光学指纹模组也可以部分或者全部集成至所述电子设备的显示屏内部，从而形成屏内(In-display或In-screen)光学指纹系统。
光学屏下指纹识别技术使用从设备显示组件的顶面返回的光来进行指纹感应和其他感应操作。该返回的光携带与该顶面接触的物体，例如手指的信息，通过采集和检测该手指返回的光，实现位于显示屏下方的特定光学传感器模块的光学指纹检测。光学传感器模块的设计可以为通过恰当地配置用于采集和检测返回的光的光学元件来实现期望的光学成像。
图1A和图2A示出了本申请实施例可以适用的电子设备的示意图。其中，图1A和图2A为电子设备10的定向示意图，图1B和图2B分别为图1A和图2A所示的电子设备10沿A-A’方向的部分剖面示意图。
所述电子设备10包括显示屏120和光学指纹模组130。其中，所述光学指纹模组130设置在所述显示屏120下方的局部区域。所述光学指纹模组130包括光学指纹传感器，所述光学指纹传感器包括具有多个光学感应单元131(也可以称为像素、感光像素、像素单元等)的感应阵列133。所述感应阵列133所在区域或者其感应区域为所述光学指纹模组130的指纹检测区域103。如图1A所示，所述指纹检测区域103位于所述显示屏120的显示区域 之中。在一种替代实施例中，所述光学指纹模组130还可以设置在其他位置，比如设置在所述显示屏120的侧面或者所述电子设备10的边缘非透光区域，并通过光路设计来将来自所述显示屏120的至少部分显示区域的光信号导引到所述光学指纹模组130，从而使得所述指纹检测区域103实际上位于所述显示屏120的显示区域。
应理解，所述指纹检测区域103的面积可以与所述光学指纹模组130的感应阵列133的面积不同，例如通过透镜成像的光路设计、反射式折叠光路设计或者其他光线会聚或者反射等光路设计，使得所述光学指纹模组130的指纹检测区域103的面积大于所述光学指纹模组130的感应阵列133的面积。在其他替代实现方式中，如果采用例如光线准直的方式进行光路引导，所述光学指纹模组130的指纹检测区域103也可以设计成与所述光学指纹模组130的感应阵列133的面积基本一致。
因此，用户在需要对所述电子设备10进行解锁或者其他指纹验证的时候，只需要将手指按压在位于所述显示屏120的指纹检测区域103，便可以实现指纹输入。由于指纹检测可以在屏内实现，因此采用上述结构的电子设备10无需其正面专门预留空间来设置指纹按键(比如Home键)，从而可以采用全面屏方案，即所述显示屏120的显示区域可以基本扩展到整个电子设备10的正面。
作为一种可选的实现方式，如图1B所示，所述光学指纹模组130包括光检测部分134和光学组件132。所述光检测部分134包括所述感应阵列133以及与所述感应阵列133电性连接的读取电路及其他辅助电路，其可以通过半导体工艺制作在一个芯片(Die)上，形成光学指纹芯片或者光学指纹传感器，也称为传感器芯片或芯片等。所述感应阵列133具体为光探测器(Photodetector)阵列，其包括多个呈阵列式分布的光探测器，所述光探测器可以作为如上所述的光学感应单元。所述光学组件132可以设置在所述光检测部分134的感应阵列133的上方，其可以具体包括滤光层(Filter)、导光层或光路引导结构、以及其他光学元件，所述滤光层可以用于滤除穿透手指的环境光，而所述导光层主要用于从手指表面反射回来的反射光导引至所述感应阵列133进行光学检测。
在具体实现上，所述光学组件132可以与所述光检测部分134封装在同一个光学指纹部件。例如，所述光学组件132可以与所述光学检测部分134 封装在同一个光学指纹芯片，也可以将所述光学组件132设置在所述光检测部分134所在的芯片外部，比如将所述光学组件132贴合在所述芯片上方，或者将所述光学组件132的部分元件集成在上述芯片之中。
其中，所述光学组件132的导光层有多种实现方案。例如，所述导光层可以具体为在半导体硅片制作而成的准直器(Collimator)层，其具有多个准直单元或者微孔阵列，所述准直单元可以具体为小孔，从手指反射回来的反射光中，垂直入射到所述准直单元的光线可以穿过并被其下方的光学感应单元接收，而入射角度过大的光线在所述准直单元内部经过多次反射被衰减掉，因此每一个光学感应单元基本只能接收到其正上方的指纹纹路反射回来的反射光，从而所述感应阵列133便可以检测出手指的指纹图像。
在另一种实现方式中，所述导光层也可以为光学透镜(Lens)层，其具有一个或多个透镜单元，例如由一个或多个非球面透镜组成的透镜组，其用于将从手指反射回来的反射光会聚到其下方的光检测部分134的感应阵列133，使得所述感应阵列133可以基于所述反射光进行成像，从而得到所述手指的指纹图像。可选地，所述光学透镜层在所述透镜单元的光路中还可以形成有针孔，所述针孔可以配合所述光学透镜层扩大所述光学指纹模组130的视场，以提高所述光学指纹模组130的指纹成像效果。
在其他实现方式中，所述导光层也可以具体采用微透镜(Micro-Lens)层，所述微透镜层具有由多个微透镜形成的微透镜阵列，其可以通过半导体生长工艺或者其他工艺形成在所述光检测部分134的感应阵列133上方，并且每一个微透镜可以分别对应于所述感应阵列133的其中一个感应单元。所述微透镜层和所述感应单元之间还可以形成其他光学膜层，比如介质层或者钝化层。进一步地，所述微透镜层和所述感应单元之间还可以包括具有微孔的挡光层(或称为遮光层、阻光层等)，其中所述微孔形成在其对应的微透镜和感应单元之间，所述挡光层可以阻挡相邻微透镜和感应单元之间的光学干扰，并使得所述感应单元所对应的光线通过所述微透镜会聚到所述微孔内部，并经由所述微孔传输到所述感应单元以进行光学指纹成像。
应理解，上述导光层的几种实现方案可以单独使用也可以结合使用。例如，可以在所述准直器层或者所述光学透镜层的上方或下方进一步设置微透镜层。当然，在所述准直器层或者所述光学透镜层与所述微透镜层结合使用时，其具体叠层结构或者光路可能需要按照实际需要进行调整。
作为一种可选的实现方式，所述显示屏120可以采用具有自发光显示单元的显示屏，比如有机发光二极管(Organic Light-Emitting Diode，OLED)显示屏或者微型发光二极管(Micro-LED)显示屏。以采用OLED显示屏为例，所述光学指纹模组130可以利用所述OLED显示屏120位于所述指纹检测区域103的显示单元(即OLED光源)作为光学指纹检测的激励光源。当手指140按压在所述指纹检测区域103时，所述显示屏120向所述指纹检测区域103上方的手指140发出一束光111，光111在手指140的表面发生反射形成反射光或者经过所述手指140内部散射而形成散射光。在相关专利申请中，为便于描述，也将上述反射光和散射光统称为反射光。由于指纹的脊(ridge)141与谷(valley)142对于光的反射能力不同，因此，来自指纹脊的反射光151和来自指纹谷的反射光152具有不同的光强，反射光经过光学组件132后，被所述光学指纹模组130中的感应阵列133接收并转换为相应的电信号，即指纹检测信号。基于所述指纹检测信号便可以获得指纹图像数据，并且可以进一步进行指纹匹配验证，从而在所述电子设备10中实现光学指纹识别功能。
在其他实现方式中，所述光学指纹模组130也可以采用内置光源或者外置光源来提供用于进行指纹检测的光信号。在这种情况下，所述光学指纹模组130可以适用于非自发光显示屏，比如液晶显示屏或者其他的被动发光显示屏。以应用在具有背光模组和液晶面板的液晶显示屏为例，为支持液晶显示屏的屏下指纹检测，所述电子设备10的光学指纹系统还可以包括用于光学指纹检测的激励光源，所述激励光源可以具体为红外光源或者特定波长非可见光的光源，其可以设置在所述液晶显示屏的背光模组下方或者设置在所述电子设备10的保护盖板下方的边缘区域，而所述光学指纹模组130可以设置液晶面板或者保护盖板的边缘区域下方并通过光路引导以使得指纹检测光可以到达所述光学指纹模组130；或者，所述光学指纹模组130也可以设置在所述背光模组下方，且所述背光模组通过对扩散片、增亮片、反射片等膜层进行开孔或者其他光学设计以允许指纹检测光穿过液晶面板和背光模组并到达所述光学指纹模组130。当采用所述光学指纹模组130采用内置光源或者外置光源来提供用于进行指纹检测的光信号时，其检测原理与上面描述内容是一致的。
应理解，在具体实现上，所述电子设备10还可以包括透明保护盖板， 所述盖板可以为玻璃盖板或者蓝宝石盖板，其位于所述显示屏120的上方并覆盖所述电子设备10的正面。因此，本申请实施例中，所谓的手指按压在所述显示屏120实际上是指按压在所述显示屏120上方的盖板或者覆盖所述盖板的保护层表面。
所述电子设备10还可以包括电路板150，电路板150设置在所述光学指纹模组130的下方。光学指纹模组130可以通过背胶粘接在电路板150上，并通过焊盘及金属线焊接与电路板150实现电性连接。光学指纹模组130可以通过电路板150实现与其他外围电路或者电子设备10的其他元件的电性互连和信号传输。例如，光学指纹模组130可以通过电路板150接收电子设备10的处理单元的控制信号，并且还可以通过电路板150将来自光学指纹模组130的指纹检测信号输出给终端设备10的处理单元或者控制单元等。
在某些实现方式中，所述光学指纹模组130可以仅包括一个光学指纹传感器，此时光学指纹模组130的指纹检测区域103的面积较小且位置固定，因此用户在进行指纹输入时需要将手指按压到所述指纹检测区域103的特定位置，否则光学指纹模组130可能无法采集到指纹图像而造成用户体验不佳。在其他替代实施例中，所述光学指纹模组130可以包括多个光学指纹传感器。所述多个光学指纹传感器可以通过拼接的方式并排设置在所述显示屏120的下方，且所述多个光学指纹传感器的感应区域共同构成所述光学指纹模组130的指纹检测区域103。从而所述光学指纹模组130的指纹检测区域103可以扩展到所述显示屏的下半部分的主要区域，即扩展到手指惯常按压区域，从而实现盲按式指纹输入操作。进一步地，当所述光学指纹传感器数量足够时，所述指纹检测区域103还可以扩展到半个显示区域甚至整个显示区域，从而实现半屏或者全屏指纹检测。
例如，如图2A和图2B所示的电子设备10，所述电子设备10中的光学指纹模组130包括多个光学指纹传感器，所述多个光学指纹传感器可以通过例如拼接等方式并排设置在所述显示屏120的下方，且所述多个光学指纹传感器的感应区域共同构成所述光学指纹模组130的指纹检测区域103。
可选地，与所述光学指纹模组130的多个光学指纹传感器相对应，所述光学组件132中可以包括多个导光层，每个导光层分别对应一个光学指纹传感器，并分别贴合设置在其对应的光学指纹传感器的上方。或者，所述多个光学指纹传感器也可以共享一个整体的导光层，即所述导光层具有一个足够 大的面积以覆盖所述多个光学指纹传感器的感应阵列。
另外，所述光学组件132还可以包括其他光学元件，比如滤光层(Filter)或其他光学膜片，其可以设置在所述导光层和所述光学指纹传感器之间，或者设置在所述显示屏120与所述导光层之间，主要用于隔离外界干扰光对光学指纹检测的影响。其中，所述滤光片可以用于滤除穿透手指并经过所述显示屏120进入所述光学指纹传感器的环境光。与所述导光层相类似，所述滤光片可以针对每个光学指纹传感器分别设置以滤除干扰光，或者也可以采用一个大面积的滤光片同时覆盖所述多个光学指纹传感器。
所述导光层也可以采用光学镜头(Lens)来代替，所述光学镜头上方可以通过遮光材料形成小孔配合所述光学镜头将指纹检测光会聚到下方的光学指纹传感器以实现指纹成像。类似地，每一个光学指纹传感器可以分别配置一个光学镜头以进行指纹成像，或者，所述多个光学指纹传感器也可以利用同一个光学镜头来实现光线会聚和指纹成像。在其他替代实施例中，每一个光学指纹传感器甚至还可以具有两个感应阵列(Dual Array)或者多个感应阵列(Multi-Array)，且同时配置两个或多个光学镜头配合所述两个或多个感应阵列进行光学成像，从而减小成像距离并增强成像效果。
在进行指纹检测时，光源照射显示屏上方的手指，光学指纹传感器采集经该手指反射或散射而返回的光信号，从而获取该手指的指纹信息。但是，由于红光和红外光会对指纹检测造成干扰。例如，在室外进行指纹检测时，太阳光中的红光和红外光可以直接透过手指到达光学指纹传感器，使得携带指纹信号的光线湮没在红光和红外光的背景噪声之中，影响了光学屏下指纹检测的性能。
为了减少红光和红外光对指纹检测的影响，可以在显示屏和光学指纹传感器之间的光路上设置滤光片，对红光和红外光进行滤除。例如，滤光片可以将600nm以上波段的红光和红外光截止，通过向外反射来减少进入光学指纹传感器的红光和红外光，从而削弱红光和红外光对有用的指纹检测信号的干扰。但是，被反射掉的红光会使显示屏的指纹检测区域内显示肉眼可见的“红斑”，从而影响了显示屏的外观，降低了用户体验。
本申请实施例的滤光片可以与光学指纹传感器集成在一起，也可以相对于光学指纹传感器独立地设置，并设置在显示屏至光学指纹传感器之间的任何位置，例如设置在导光层的上方。
当滤光片相对于光学指纹传感器独立地设置时，需要保证该滤光片的结构稳定性，避免滤光膜层发生“翘曲”等现象。
为此，本申请实施例提供一种滤光片，能够有效地滤除非目标波段的光信号，提高指纹识别的性能，并且避免了“红斑”的产生，不会对显示屏的外观带来影响，同时具有良好的结构稳定性。
图3和图4所示为一种可能的滤光片的示意图。如图3所示，基底400的上表面覆盖有一层减反(Anti-Reflective Coating，AR)膜层401(也称为增透膜或者减反增透膜)，用于增加穿过滤光片的光信号，减少被反射的光信号。基底400的下表面依次覆盖有紫外(Ultraviolet，UV)膜层402和红外(Infrared Radiation，IR)膜层403，其中，UV膜层402的截止波长例如可以位于400nm-420nm之间，用于反射掉其截止波长以下的波段内的紫光和紫外光，IR膜层403的截止波长例如位于600nm-620nm之间，用于反射掉其截止波长以上的波段内的红光和红外光。通过这种膜系搭配，可以实现对400nm-620nm范围内可见光的高透光率，以及对红光和红外光的有效截止，从而实现有效的指纹检测。或者，如图4所示，UV膜层402可以设置在基底400的上表面，AR膜层401设置在UV膜层402的上表面，IR膜层403设置在基底的下表面。其中，AR膜层401为非必须的膜层，通常在对透过率有较高需求的场景下使用。
但是，在图3和图4中，被IR膜反射的红光会到达显示屏并进入人眼使得用户可以看到显示屏的指纹检测区域内呈现“红斑”，从而影响用户体验。
为此，本申请实施对滤光片做了进一步改进，在保证指纹检测性能的同时不影响用户的视觉感受，并具有良好的结构稳定性。
图5是本申请实施例的滤光片500的示意性框图。所述滤光片500设置于显示屏与光学指纹传感器之间，所述光学指纹传感器用于检测所述显示屏上方的手指返回的光信号，所述滤光片500用于过滤所述光信号传输至所述光学指纹传感器的光路中的非目标波段的光信号。如图5所示，所述滤光片包括：
基底510；
至少一个截止膜层520，用于反射所述非目标波段的光信号；以及，
至少一个吸收层530，用于吸收所述非目标波段的光信号。
其中，所述至少一个截止膜层520位于所述基底510的两侧。
所述非目标波段的光信号包括红光波段的光信号和红外波段的光信号。
所述红光波段的光信号的波长例如位于620纳米至770纳米之间，以下也称为红光；所述红外波段的光信号的波长例如位于770纳米至1000纳米之间，以下也称为红外光。
进一步地，所述非目标波段的光信号还可以包括紫光波段的光信号和紫外波段的光信号，以下也分别称为紫光和紫外光。
在进行指纹检测时，通常会滤除长波段的红光和红外光，以及短波段的紫光和紫外光，从而使例如400-620纳米波段内的可见光到达光学指纹传感器，以实现最优的指纹检测性能。
该实施例中，通过在基底两侧设置能够吸收红光和红外光的吸收层以及使红光和红外光截止的截止膜层，减小了红光和红外光对指纹检测性能的影响，并且由于吸收层对红光的吸收，避免了显示屏上呈现明显的“红斑”，在保证指纹检测性能的同时不会对用户视觉感受带来影响。另外，由于各个截止膜层可以合理地设置在基底的两侧，该滤光片不易发生应力不均导致的膜层“翘曲”现象，具有良好的结构稳定性。
基底510例如可以是玻璃基底或者树脂基底。
基底510对波长为450-600纳米的光信号的透光率例如为80％-90％。
可选地，至少一个截止膜层520可以包括IR膜层和/或UV膜层。
至少一个截止膜层520例如可以通过溅射、镀膜或沉积等方式形成。
其中，IR膜层的截止波长例如可以位于620-680纳米之间，能够将截止波长以上波段的光线反射掉，从而使该波段的光信号不会被光学指纹传感器采集到，避免了红光和红外光对有用的指纹检测信号造成影响。
UV膜层的截止波长例如可以位于400-420纳米之间，能够将截止波长以下波段的光线反射掉，使得紫光和紫外光不会被光学指纹传感器采集到。一方面，由于紫光和紫外光的波长较短，光线能量相对较高，容易使光路中的有机材料层，例如微透镜阵列、滤光片500中的IR膜层和吸收层等发生老化，因此可以在滤光片500中增加UV膜层；另一方面，UV膜层可以用来平衡IR膜层，例如，在基底510的两侧分别设置IR膜层和UV膜层时，可以使基底510两侧的膜层应力达到均衡，避免了应力不均匀导致的膜层“翘曲”，提高了滤光片的结构稳定性。
可选地，所述至少一个吸收层530包括油墨层和/或青色涂料层。
油墨层和青色涂料层例如可以通过旋涂等方式形成。
其中，油墨层和青色涂料层都可以用来吸收红光和红外光，但是两者的材料特性不同。
油墨容易因氧化等原因导致其吸光性能变差，因此，本申请实施例中，优选地，油墨层涂覆在基底510的上表面和/或下表面。进一步地，在油墨层的外侧制作截止膜层，该截止膜层可以用于将非目标波段的光线反射掉，并且可以在油墨层的外侧对油墨层进行保护。
例如，所述基底510的上表面覆盖有所述UV膜层，所述基底510的下表面依次覆盖有所述油墨层和所述IR膜层。
又例如，所述基底510的上表面依次覆盖有所述油墨层和所述UV膜层，所述基底510的下表面覆盖有所述IR膜层。
又例如，所述基底510的上表面依次覆盖有所述油墨层和所述UV膜层，所述基底510的下表面依次覆盖有所述油墨层和所述IR膜层。
青色涂料层对红光具有很好的吸收能力，基于光的三原色，蓝光和绿光的结合即是青色，青色中不含有红光成分，红色与青色为互补色，能够相互吸收对方的颜色，因此采用青色涂料对红光进行吸收具有很好的效果。但是，青色涂料层容易受到电流、温度等的影响，在进行IR膜和UV膜的镀制时，高温环境可能导致青色涂料的性质发生变化，影响其吸光性能。因此，本申请实施例中，优选地，青色涂料层位于所述滤光片的最外侧。在制作该滤光片时，基底两侧的其他膜层制作完成后，再涂覆该青色涂料层。
例如，所述基底510的上表面依次覆盖有所述UV膜层和所述青色涂料层，所述基底510的下表面覆盖有所述IR膜层。
又例如，所述基底510的上表面覆盖有所述UV膜层，覆盖于所述基底510的下表面依次覆盖有所述IR膜层和所述青色涂料层。
又例如，所述基底510的上表面依次覆盖有所述UV膜层和所述青色涂料层，所述基底510的下表面依次覆盖有所述IR膜层和所述青色涂料层。
使用油墨层和青色涂料层，主要是为了吸收红光，因为红光为可见光，会使显示屏上的指纹检测区域内呈现肉眼可见的“红斑”。而红外光为不可见光，因此不会对显示屏的外观带来较大影响。但是，油墨层和青色涂料层也可以用于吸收一部分的红外光，例如近红外光，从而加强滤光片500对红光和红外光的滤除能力。可选地，在吸收层对红光和红外光的吸收光谱中，半 波(T50，即透过率为50％处对应的波长)可以为位于540～680nm之间。
下面结合图6至图11，描述图5所示的滤光片500的几种可能的实现方式。其中，在图6至图8中，至少一个吸收层530包括一个或多个油墨层。在图9至图11中，至少一个吸收层530包括一个或多个青色涂料层。
如图6所示，基底510的上表面覆盖有UV膜层521，可以通过例如溅射、蒸镀或沉积的方式制作在基底510的上表面。UV膜层521的截止波长可以位于400-420纳米之间，用于将紫光和紫外光向外反射，以阻止紫光和紫外光到达光学指纹传感器。基底510的下表面涂覆有油墨层5311，用于吸收红光波段的光信号。油墨层5311的下表面是IR膜层522，可以通过例如溅射、蒸镀或沉积的方式制作在油墨层5311的下表面。IR膜层522的截止波长可以位于620-680纳米之间，用于将红光和红外光向外反射，以阻止红光和红外光传输至光学指纹传感器。
油墨层5311可以如图6中所示，位于基底510的下表面。油墨层5311也可以位于基底510的上表面，例如图7所示。在图7中，油墨层5311涂覆在基底510的上表面，而UV膜层521镀制在油墨层5311的上表面。IR膜层522镀制在基底510的下表面。
或者，基底510的下表面和上表面都可以制作油墨层。例如图8所示，基底510的上表面和下表面分别涂覆有油墨层5311和油墨层5312，用于吸收红光波段的光信号。在油墨层5311的上表面镀制有UV膜层521，用于滤除紫光和紫外光。并且在油墨层5312的下表面镀制有IR膜层522，从而实现对红光和红外光的滤除。
在图6至图8中，油墨层均涂覆在基底的上表面和/或下表面，而UV膜层和IR膜层覆盖在油墨层的外表面，从而可以对油墨层进行保护。
如图9所示，基底510的上表面覆盖有UV膜层521，可以通过例如溅射、蒸镀或沉积的方式制作在基底510的上表面。UV膜层521的截止波长可以位于400-420纳米之间，用于将紫光和紫外光向外反射，以阻止紫光和紫外光到达光学指纹传感器。UV膜层521的上表面涂覆有青色涂料层5321，用于吸收红光波段的光信号。基底510的下表面镀制有IR膜层522，可以通过例如溅射、蒸镀或沉积的方式制作在基底510的下表面。IR膜层522的截止波长可以位于620-680纳米之间，用于将红光和红外光向外反射，以阻止红光和红外光传输至光学指纹传感器。
青色涂料层5321可以如图9中所示，位于基底510的上侧。青色涂料层5321也可以位于基底510的下侧，例如图10所示。在图10中，IR膜层522镀制在基底510的下表面，而青色涂料层5321涂覆在IR膜层522的下表面。UV膜层521镀制在基底510的上表面。
或者，基底510的下侧和上侧都可以设置青色涂料层。例如图11所示，基底510的上表面和下表面分别镀制有UV膜层521和IR膜层522，用于实现对紫光和紫外光、以及红光和红外光的滤除。UV膜层521的上表面涂覆有青色涂料层5321。IR膜层522的下表面涂覆有青色涂料层5322。青色涂料层5321和青色涂料层5322可以用于实现对红光和红外光的滤除。
在图9至图11中，青色涂料层均涂覆在UV膜层和IR膜层的外侧。在制作滤光片时，可以先将UV膜层和IR膜层镀制在基底的上表面和下表面，并在UV膜和/或IR膜的外侧涂覆该青色涂料层。这样，UV膜层和IR膜层可以在高温工艺下进行镀制，之后再涂覆该青色涂料层时，就不会受到镀膜温度等工艺的影响。
其中，上述的UV膜层521与IR膜层522可以分别镀制在基底510的两侧，也可以镀制在基底510的同一侧。其中，当UV膜层521设置于基底510的上侧，而IR膜层522设置于基底的下侧时，既可以避免基底两侧应力不均造成的膜层“翘曲”，也可以优先滤除能量较高的紫光和紫外光，避免其对IR膜层522造成损伤。例如图6所示，UV膜层521镀制在基底510的上表面，而油墨层5311和IR膜层522分别位于基底510的下表面，因此入射至滤光片500的光线先经过UV膜层521，从而使到达油墨层5311和IR膜层522的光线中的紫光和紫外光成分明显降低。另外，当滤光片500设置于微透镜阵列的上方时，还能够防止紫光和紫外光的长期照射对微透镜阵列的影响。其中，可以理解，微透镜阵列也是一层聚合物有机膜。
在图6至图8中，油墨层位于IR膜层522的上方，例如图6和图7中所示，从上方入射至滤光片的光线，先到达UV膜层521，使紫光和紫外光被滤除。其余光线进入油墨层5311，其中的红光和红外光可以被油墨层5311吸收。未被油墨层5311吸收的红光和红外光到达IR膜层522，从而被IR膜层522反射。被IR膜层522反射的红光和红外光可以被IR膜层522上方的油墨层5311进行二次吸收。而目标波段的光线透过IR膜层522到达光学指纹传感器。这样，不仅通过IR膜层522对红光和红外光进行反射，并且通 过油墨层5311对红光和红外光进行吸收，使得红光和红外光即不会对指纹检测信号造成干扰，也不会在显示屏上呈现“红斑”而影响用户的视觉感受，从而实现光学指纹检测的性能与外观的良好平衡。
类似地，在图9中，青色涂料层位于IR膜层522上方。从上方入射至滤光片的光线，先到达青色涂料层5321，其中的红光和红外光可以被青色涂料层5321吸收。其余光线进入UV膜层521，进一步使紫光和紫外光被滤除。未被油墨层5311吸收的红光和红外光，接下来透过基底510到达IR膜层522，从而被IR膜层522反射。被IR膜层522反射的红光和红外光可以被IR膜层522上方的青色涂料层5321进行二次吸收。而目标波段的光线透过IR膜层522到达光学指纹传感器。这样，不仅通过IR膜层522对红光和红外光进行反射，并且通过青色涂料层5321对红光和红外光进行吸收，使得红光和红外光即不会对指纹检测信号造成干扰，也不会在显示屏上呈现“红斑”而影响用户的视觉感受，从而实现光学指纹检测的性能与外观的良好平衡。
但是，本申请对吸收层和IR膜层的上下位置关系不做限定。吸收层也可以位于IR膜层的下方。以吸收层为青色涂料层为例，如图10所示，可以设置IR膜层的截止波长较大，例如为680纳米。这样，经过UV膜511之后的光线到达IR膜层522时，其中的680纳米以上红光和红外光被IR膜层522反射回去，而其余红光到达IR膜层522下方的青色涂料层5321从而被吸收。由于680纳米以上的光线中可见光的成分较低，对人眼视觉的影响较小，反射回去的这些光线在显示屏上呈现的“红斑”并不明显，不会对用户的视觉体验造成较大的影响。因此，通过将IR膜层522的截止波长设置的较大，使得IR膜层522能够设置在青色涂料层5321的上方，从而便于青色涂料层5321覆盖在IR膜层522的外侧，以避免制作过程中对青色涂料层5321的吸光性能造成影响。
以上仅仅为示例，任何IR膜层搭配吸收层的滤光片的设计方式，均落入本申请的保护范围。
滤光片中可以包括一个油墨层或者多个油墨层。该油墨层可以位于IR膜层的上方，例如图6和图7所示；该油墨层也可以位于IR膜层的下方，并且当油墨层位于IR膜层的下方时，IR膜层的截止波长可以设置较大的值；或者，分别在基底两侧设置两个油墨层，例如图8所示。
滤光片中也可以包括一个青色涂料层或者多个青色涂料层。该青色涂料 层可以位于IR膜层的上方，例如图9所示；该青色涂料层也可以位于IR膜层的下方，例如图10所示，并且当青色涂料层位于IR膜层的下方时，IR膜层的截止波长可以设置较大的值；或者，分别在基底两侧设置两个青色涂料层，例如图11所示。
当然，该滤光片中也可以同时使用油墨层和青色涂料层，以实现更好的吸光效果。
上述不同的吸收层的位置及涂覆的层数可以根据实际情况进行调整，从而满足外观需求和指纹检测性能的需求。
可选地，所述滤光片500中还可以包括其他膜层，例如AR膜层等。所述AR膜层用于提高所述滤光片500对目标波段的光线的透过率。通常，在对透过率有较高需求的场景下，可以在滤光片500中设置AR膜层。所述AR膜层还可以用来平衡其他膜层例如IR膜层，以使基底510两侧的膜层应力达到均衡，避免应力不均匀导致的膜层“翘曲”。
本申请实施例对截止膜层的镀膜层数，以及吸收层的厚度均不作限定。
例如，至少一个截止膜层520的镀膜层数位于10-80之间。比如在图6至图11中，UV膜层和IR膜层的镀膜层数之和位于10-80层之间。
又例如，至少一个吸收层530的厚度位于1-30微米之间。比如在图6至图11中，油墨层的总厚度或者青色涂料层的总厚度位于1-30微米之间。
本申请实施例中，所述滤光片可以作为与光学指纹传感器相对独立的部件，设置在从显示屏至光学指纹传感器之间的光路中的任何位置，以对手指返回的光信号进行过滤，从而过滤掉非目标波段的光信号，以使目标波段的光信号到达光学指纹传感器。
例如，所述滤光片设置在所述显示屏与导光层之间，所述导光层用于将经过所述滤光片之后的目标波段的光信号会聚至所述光学指纹传感器。
所述导光层可以包括光学准直器、镜头、或者微透镜阵列。其中，光学准直器、镜头、或者微透镜阵列的具体细节可以参考前述针对图1B和图2B中的相关描述，为了简洁，这里不再赘述。
例如图12所示，滤光片500设置在微透镜阵列610的上方。滤光片500与微透镜阵列610之间可以是空气，也可以填充透光介质。并且微透镜阵列610的四周还可以设置遮光材料。微透镜阵列600的下方依次设置有挡光层620、挡光层630以及光学指纹传感器710。微透镜阵列610、挡光层620、 挡光层630和光学指纹传感器710之间可以填充有透光介质。其中，微透镜阵列610用于对显示屏上方的手指返回的光信号进行会聚。挡光层620和挡光层630上均设置有与各个微透镜对应的开孔。经每个微透镜会聚后的光信号依次穿过挡光层620和挡光层630中与该微透镜对应的开孔，到达光学指纹传感器710的感应单元。例如，微透镜611会聚的光线依次经过挡光层620上的开孔621以及挡光层630上的开孔631到达感应单元711。
本申请实施例还提供了一种指纹检测的装置，如图13所示，该装置1300包括：光学指纹传感器1310、以及上述本申请各种实施例中的滤光片500。
其中，所述滤光片500用于将手指返回的光信号中位于目标波段的光信号，传输至光学指纹传感器1310。
本申请实施例还提供了一种电子设备，该电子设备包括：显示屏、以及上述本申请各种实施例中的指纹检测的装置1300。
所述显示屏可以为普通的非折叠显示屏，也可以为可折叠显示屏或称为柔性显示屏。
作为示例而非限定，本申请实施例中的电子设备可以为终端设备、手机、平板电脑、笔记本电脑、台式机电脑、游戏设备、车载电子设备或穿戴式智能设备等便携式或移动计算设备，以及电子数据库、汽车、银行自动柜员机(Automated Teller Machine，ATM)等其他电子设备。该穿戴式智能设备包括功能全、尺寸大、可不依赖智能手机实现完整或部分的功能，例如：智能手表或智能眼镜等，以及只专注于某一类应用功能，需要和其它设备如智能手机配合使用，如各类进行体征监测的智能手环、智能首饰等设备。
需要说明的是，在不冲突的前提下，本申请描述的各个实施例和/或各个实施例中的技术特征可以任意的相互组合，组合之后得到的技术方案也应落入本申请的保护范围。
应理解，本申请实施例中的具体的例子只是为了帮助本领域技术人员更好地理解本申请实施例，而非限制本申请实施例的范围，本领域技术人员可以在上述实施例的基础上进行各种改进和变形，而这些改进或者变形均落在本申请的保护范围内。
以上所述，仅为本申请的具体实施方式，但本申请的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本申请揭露的技术范围内，可轻易想到变化或替换，都应涵盖在本申请的保护范围之内。因此，本申请的保护 范围应以所述权利要求的保护范围为准。

Claims (24)

  1. 一种滤光片，其特征在于，所述滤光片设置于显示屏与光学指纹传感器之间，所述光学指纹传感器用于检测所述显示屏上方的手指返回的光信号，所述滤光片用于过滤所述光信号传输至所述光学指纹传感器的光路中的非目标波段的光信号，所述非目标波段的光信号包括红光波段的光信号和红外波段的光信号，所述滤光片包括：
    基底；
    至少一个截止膜层，用于反射所述非目标波段的光信号，其中，所述至少一个截止膜层位于所述基底的两侧；以及，
    至少一个吸收层，用于吸收所述非目标波段的光信号。
  2. 根据权利要求1所述的滤光片，其特征在于，所述至少一个吸收层包括油墨层和/或青色涂料层。
  3. 根据权利要求1或2所述的滤光片，其特征在于，所述至少一个截止膜层包括红外IR膜层和/或紫外UV膜层。
  4. 根据权利要求3所述的滤光片，其特征在于，所述IR膜层的截止波长位于620纳米至680纳米之间。
  5. 根据权利要求3或4所述的滤光片，其特征在于，所述UV膜层的截止波长位于400纳米至420纳米之间。
  6. 根据权利要求3至5中任一项所述的滤光片，其特征在于，所述至少一个吸收层包括油墨层，其中，所述油墨层涂覆在所述基底的上表面和/或下表面。
  7. 根据权利要求6所述的滤光片，其特征在于，
    所述基底的上表面覆盖有所述UV膜层，
    所述基底的下表面依次覆盖有所述油墨层和所述IR膜层。
  8. 根据权利要求6所述的滤光片，其特征在于，
    所述基底的上表面依次覆盖有所述油墨层和所述UV膜层，
    所述基底的下表面覆盖有所述IR膜层。
  9. 根据权利要求6所述的滤光片，其特征在于，
    所述基底的上表面依次覆盖有所述油墨层和所述UV膜层，
    所述基底的下表面依次覆盖有所述油墨层和所述IR膜层。
  10. 根据权利要求3至5中任一项所述的滤光片，其特征在于，所述至 少一个吸收层包括青色涂料层，其中，所述青色涂料层位于所述滤光片的最外侧。
  11. 根据权利要求10所述的滤光片，其特征在于，
    所述基底的上表面依次覆盖有所述UV膜层和所述青色涂料层，
    所述基底的下表面覆盖有所述IR膜层。
  12. 根据权利要求10所述的滤光片，其特征在于，
    所述基底的上表面覆盖有所述UV膜层，
    覆盖于所述基底的下表面依次覆盖有所述IR膜层和所述青色涂料层。
  13. 根据权利要求10所述的滤光片，其特征在于，
    所述基底的上表面依次覆盖有所述UV膜层和所述青色涂料层，
    所述基底的下表面依次覆盖有所述IR膜层和所述青色涂料层。
  14. 根据权利要求1至13中任一项所述的滤光片，其特征在于，所述红光波段的光信号的波长位于620纳米至770纳米之间，所述红外波段的光信号的波长位于770纳米至1000纳米之间。
  15. 根据权利要求1至14中任一项所述的滤光片，其特征在于，所述至少一个截止膜层的镀膜层数位于10-80之间。
  16. 根据权利要求1至15中任一项所述的滤光片，其特征在于，所述至少一个吸收层的厚度位于1-30微米之间。
  17. 根据权利要求1至16中任一项所述的滤光片，其特征在于，所述滤光片还包括：
    减反AR膜层，用于提高所述滤光片对目标波段的光线的透过率。
  18. 根据权利要求1至17中任一项所述的滤光片，其特征在于，所述基底为玻璃或树脂。
  19. 根据权利要求1至18中任一项所述的滤光片，其特征在于，所述基底对波长为450纳米至600纳米的光信号的透光率为80％-90％。
  20. 根据权利要求1至19中任一项所述的滤光片，其特征在于，所述至少一个截止膜层通过溅射、镀膜或沉积的方式形成。
  21. 根据权利要求1至20中任一项所述的滤光片，其特征在于，所述滤光片设置在所述显示屏与导光层之间，所述导光层用于将经过所述滤光片之后的目标波段的光信号会聚至所述光学指纹传感器。
  22. 根据权利要求21所述的滤光片，其特征在于，所述导光层包括光 学准直器、镜头、或者微透镜阵列。
  23. 一种指纹检测的装置，其特征在于，所述装置设置于显示屏下方，以实现光学屏下指纹检测，所述装置包括：
    光学指纹传感器；以及，
    根据权利要求1至22中任一项所述的滤光片。
  24. 一种电子设备，其特征在于，包括：
    显示屏；以及，
    根据权利要求23所述的指纹检测的装置。
PCT/CN2019/108584 2019-09-27 2019-09-27 滤光片、指纹检测的装置和电子设备 WO2021056425A1 (zh)

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